The conventional press-type fastener is commonly used in the exercise devices. As shown in FIG. 1, a prior art press-type fastener comprises a toothed belt 10 and a fastening set. The fastening set is composed of a base 11, a fastening block 12, a retaining base 13, and a retaining block 14. The base 11 is provided at the center thereof with two fastening holes 15 and is further provided with two pivoting lugs 16 having a pin hole 17. The fastening block 12 has an arm 18, a round hole 19 and a slot 20. The retaining base 13 is provided respectively on two sides thereof with a pivoting lug 21 having a pin hole 22. The retaining block 14 is provided at the front end thereof with a projection 23 and at the rear end thereof with a toothed face 24 and further at the center thereof with an elongated hole 25. The arm 18 of the fastening block 12 is fastened pivotally with the pivoting lug 16 of the base 11 by means of a rivet 26 which is received in the pin hole 17 and the round hole 19. The retaining base 13 and the retaining block 14 are fastened pivotally with the base 11 in conjunction with a spring 28 by means of a long pin 27 which is received in the slot 20.
In operation, the toothed belt 10 is inserted into the retaining base 13 and is then located by the retaining block 14 in conjunction with the spring 28. As the fastening block 12 is pulled down, the fastener makes the exercise device secure.
Such a prior art press-type fastener as described above has inherent shortcomings, which are expounded explicitly hereinafter.
The toothed belt 10 does not work precisely as expected in view of the fact that the fastening block 12 must be pulled open each time when the toothed belt 10 is adjusted.
The toothed belt 10 is vulnerable to damage or breakage under a great, pressure of the fastening block 12 in view of the fact that the toothed belt 10 is not securely located by the retaining block 14.
The prior art press-type fastener is devoid of a microadjustment device capable of facilitating the use of the exercise device by an exerciser with ease and speed.